The present application is based on and claims priority from Japanese Patent Application Hei 10-312031 filed on Nov. 2, 1998, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an ac generator for a vehicle such as a passenger car or a truck.
2. Description of the Related Art
Recently, in order to reduce vehicle outside and inside noises, engine noise has been reduced. Accordingly, magnetic noise caused by ac generators has become relatively harsh. As vehicle electric loads have increased, the output power of ac generators has also increased, resulting in an increase of the magnetic noise.
In the conventional ac generator, round magnetic wires are used for a stator winding, which is installed into a cylindrical stator core. JP-A-7-231591 discloses a stator having a stator winding disposed in slots and retained by wedges.
However, in the stator core of such a conventional ac generator, teeth are not supported in the circumferential direction by other members. Therefore, the teeth may vibrate in the circumferential direction due to vibration of the stator winding while the ac generator is driven to generate electric power.
Although the above stated stator core has wedges for retaining the stator winding, it is preferable to omit the wedges to reduce production cost. However, if the wedges are omitted, it is difficult to prevent salt water or muddy water from entering the slots. This may deteriorate the insulation of the stator winding and slots.
An object of the invention is to provide a low-noise and corrosion resistant ac generator.
According to an embodiment of the invention, a stator winding having a plurality of radially aligned in-slot portions disposed in each slot to form a gap at the radially central portion thereof, and at least one of the in-slot portions is or are disposed at the radially inner side of each slot. Therefore, each slot is effectively closed by the in-slot portions and teeth between the slots are supported by the in-slot portions from opposite circumferential sides.